Migrating from Interbase Express (IBExpress) to FireDAC

In my last blog I explained how to migrate from BDE to FireDAC. Here I will show you how to migrate a client-server application using Interbase Express data access components, such as TIBDatabase, TIBTransaction, TIBQuery, TTable, to the FireDAC. It shows the basic principles of replacing the common components, properties and code, preserving the developers working time and avoiding the common migration pitfalls.

So lets start in steps.

1. Units Changed

We need to replace used IBExpress units to FireDAC units.

Find 

IBDatabase, IBCustomDataSet, IBTable, IBStoredProc, IBQuery, IBUpdateSQL, IBSQL, IBDatabaseInfo, IBEvents, IBScript

Replace

          FireDAC.Stan.Intf, FireDAC.Stan.Option, FireDAC.Stan.Error, FireDAC.UI.Intf,

FireDAC.Phys.Intf, FireDAC.Stan.Def, FireDAC.Phys, FireDAC.Stan.Pool,

FireDAC.Stan.Async, FireDAC.Stan.Param, FireDAC.DatS, FireDAC.DApt.Intf,

FireDAC.DApt, FireDAC.Comp.Client, FireDAC.Comp.DataSet

2. IBExpress components classes compatible with FireDAC

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
TIBDatabase	TFDConnection
TIBTransaction	TFDTransaction
TIBTable	TFDTable
TIBQuery	TFDQuery
TIBStoredProc	TFDStoredproc
TIBSQL	TFDCommand
TIBUpdateSQL	TFDUpdateSQL
TIBDatabaseInfo	TFDIBInfo
TIBScript	TFDScript

3. Other Types classes changed

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
TParams	TFDParams
TBlobStream	TFDBlobStream
TBDEDataSet	TFDRDBMSDataSet

4. TIBDatabase -> TFDConnection Properties

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
DatabaseName	ConnectionName
DefaultTransaction	Transaction
ServerType	Not Supported so remove.
TraceFlags	Not Supported so remove.

Note* - OnLogin Event

TIBDatabase.OnLogin event is different than TFDConnection.OnLogin. So we should remove Tdatabase event and re-write TFDConnection Event.

5. TIBTransaction -> TFDTransaction Properties

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
DefaultDatabase	Connection
Active	Not Supported so remove.
AllowAutoStart	Options.AutoStart
AutoStopAction	Not Supported so remove.
DefaultAction	Not Supported so remove.
Params	Options.Params

  

6. TIBTable -> TFDTable Properties

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
BufferChunks	FormatOptions.InLineDataSize
Database	Connection
Readonly	UpdateOptions.Readonly
StoreDefs	Not Supported so remove.
TableTypes	Not Supported so remove.
Unidirectional	FetchOptions.Unidirectional

7. TIBQuery -> TFDQuery Properties

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
BufferChunks	FormatOptions.InLineDataSize
Database	Connection
Datasource	MasterSource Note. Please check MasterFields
GeneratorName	UpdateOptions.GeneratorField
Datasource	MasterSource Note. Please check MasterFields
ParamCheck	ResourceOptions.Paramcreate
Requestlive	UpdateOptions.Requestlive
Unidirectional	UpdateOptions.Unidirectional

8. TIBStoredProc -> TFDStoredProc        Properties

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
Database	Connection

9. TIBSQL -> TFDCommand  Properties

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
Database	Connection
ParamCheck	ResourceOptions.Paramcreate
SQL	CommandText

10. TIBUpdateSQL -> TFDUpdateSQL      Properties

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
	Connection
RefreshSQL	FetchSQL

10. TIBDatabaseInfo -> TFDInfo    Properties

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
Database	DriverLink

11. TIBScript -> TFDScript    Properties

Search IBEXPRESS classes and replace with FireDAC classes

IBEXPRESS	FireDAC
Database	Connection
Dataset	Not Supported so remove
Scripts	SQLScripts
Terminator	ScriptOptions.CommandSeparator

12. Sorting

FireDAC components like TFDQuery, TFDTable does not have Sort property. So we have to use IndexFieldNames property for sorting. So where ever we have used Sort for sorting in our project we need to replace with IndexFieldNames like follow.

ADQuery1.IndexFieldNames := 'ORDERID';

or

ADQuery1.IndexFieldNames := 'OrderDate:D;Price'; //D for descending//

13. TBookMark Changes for Dataset components

When we save a bookmark for future use we must use pointer for

var

BookMark : Pointer;

CDS : TClientDataset

……

// Required so your assignment doesn't attempt to free a non-existent bookmark //

 Bookmark := nil;

 TBookmark(Bookmark) := CDS.GetBookmark;

14. Data Property

If we use TFDQuery and ClientDataset together then Data property is mostly used to assign saved data to any other dataset component directly instead of using any loop. Here TFDQuery have also Data property but type is different. Earlier in TADOQuery or other Query component, Data property was OleVariant type which was same type like ClientDataset but now it is IFDDataSetReference. 

So we cannot just assign directly like.

Clientdataset1.Data := FDQuery.Data; //will result an error //

Above code will compile successfully but will result “Invalid data packet” error at runtime. In this scenario we have to use TDatasetProvider as mediator to transfer data from once dataset to another. We can use DatasetProvider.Data property like follow.

DataSetProvider1.Dataset := FDQuery1;

FdQuery1.Open;

Clientdataset1.data := DatasetProvider1.data;

15. Extra points to check

a. Need to change some numeric fields to TBCDFields when it will show error and set Size=2 when in Database field type is like number(15,2)

b. Check SQL statement for “. If it is like “DBA.Segments” which is wrong then it should be “DBA”.”Segment” or DBA.Segments